WO96/40634 describes that 2-amino-3-cyano-4-methyl-5-(2-fluorophenyl)pyrrole (hereinafter referred to as the pyrrole compound) has excellent urinary bladder capacity increasing activity and is useful for the treatment of pollakiuria or urinary incontinence. Also Examples 5-(1) and 5-(2) of the above publication describe that crystal (hereinafter referred to as type-II crystal) of the pyrrole compound by recrystallizing the pyrrole compound from a mixed solvent (1:1) of benzene and n-hexane, or benzene.